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Astrocytomas are typically described as low grade astrocytomas (LGAs) or high grade astrocytomas (HGAs) based on pathological characteristics.

Low Grade Astrocytomas (LGA)


Grow slowly over a long period of time

Most LGA are of two types:

1. Pilocytic astrocytoma (PA)

    • World Health Organization [WHO] grade I
    • Circumscribed
    • Homogeneously neoplastic
    • Low potential for tissue infiltration or malignant degeneration
    • Lacks p53 changes, but may show loss of chromosome 17q in the region of
      the NF1 gene

2. Diffuse fibrillary astrocytoma (DA)

    • WHO grade II
    • Invasive tumor
    • Tendency to undergo malignant change (esp in adults)
    • Genetically distinct - associated frequently with p53 mutations or occasionally
      with loss of heterozygosity on chromosome 10p.

Other Low-Grade Astrocytomas:

  • Pleomorphic Xanthoastrocytoma (PXA)
    • Form of astrocytoma unique to children
    • More common in late childhood and early adolescence
  • Subependymal Giant Cell Astrocytoma
  • Dysembryoplastic Neuroepithelial Tumor (DNET)
    • some would argue that these are neuroepithelial tumors rather than gliomas
  • Ganglioglioma
  • Oligodendroglioma
  • Desmoplastic infantile ganglioglioma

Characteristics of Low-Grade Astrocytomas:


Pilocytic Astrocytoma(JPA)

Desmoplastic Cerebral Astrocytoma

Subependymal Giant Cell Astrocytoma

Fibrillary [P1]

Most Common

Patient Age

Early childhood

Usually <2 years


Early childhood, may be as early as neonatal period


Most Common Tumor Location


Cerebral hemispheres

Subependymal origin


Occur along lining of lateral ventricles

Brain parenchyma


May be supratentorial



Indolent nature

Invade leptomeninges

Grows to invade 4th ventricle


May obstruct foramen of Munro

Diffuse infiltration of parenchyma


Anaplastic progression




Solid and cystic architectural pattern


Rosenthal fibers


Commonly has vascular proliferation

Highly spindled cells




Both glial and neuronal nature suggested


Reactive with both types of tumor markers


Lineage still debated


Large cells with abundant cytoplasm


Occasional calcification


Fibrillary pattern may be seen

Nuclei of normal astrocytes, but may be pleomorphic


No mitotic figures


No vascular proliferation


No necrosis

Special Features

Unique to children

Their association with basal lamina may be responsible for their indolent nature


Extracellular matrix proteins inhibit cell growth

Associated with tuberous sclerosis[P2]

Lack contrast enhancement


Very good:

  • Indolent nature
  • -Long term prognosis related to location

Favorable, even with large size

Total resection is the best option for progression-free survival


High-grade astrocytomas

  • Worse prognosis than LGA
    • Higher rate of neuraxis dissemination
    • Grow rapidly
  • Two main classes of high grade astrocytomas:
    • anaplastic astrocytomas
    • glioblastoma multiforme

Characteristics of High Grade Astrocytomas:

Anaplastic Astrocytoma

Glioblastoma Multiforme (GBM)

Patient Age

Uncommon in children


Tend to occur in adults

(median age 40yrs)

Uncommon in children


Tend to occur in adults (median age 45-70yrs).

Tumor Location

Cerebral hemispheres

Brain stem

Subcortical white matter of cerebral hemispheres


Increase in cellularity


Nuclear pleomorphism




May have mitosis & vascular proliferation


No necrosis

  • if present, would be GBM

Dense cellularity


Mitotic figures


Vascular proliferation


Necrosis is present


High incidence of progression to glioblastoma

Very poor prognosis


External Link:

Overview of Astrocytomas at the Atlas of Genetics and Cytogenetics in Haematology and Oncology



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